Bug Fix 015, Robot Vacuum, and trainable stocking shelves!

[list] [*] Fixed a few bugs that were occurring with the mop and bucket interaction. [*] Added new furniture: Robot Vacuum. [*] Stockers will now only stock product shelves that a player has placed an item type on. To train a shelf slot on a new item, manually place the product you want on the shelf, and it will overwrite the previous product. [/list]